(My experiens is that the best is to buy directly from Halgöfs - but I am in Sweden, so I do not know how it works to other countries. Otherwise some company dealing with equipment for forestry, in Sweden Skogma, http://www.skogma.se/ but I guess there are some similar company in Finland)

I am using a 40 cm (2 threaded) and a 25 cm (3 threaded) Haglöfs. The short one works best in log-houses of coniferous wood. The long one is useful for living trees and for big oak beams (mainly in wind mills...). There are several diamerers, but the 5 mm is the best for our purpose, I think. Maybe a 30 cm 3 treaded may be a good compromise, if you will be working with pine and spruce mainly.